From 9238fa35a3c04835a77988a14e1397763cf0eabe Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Mon, 24 Nov 2025 13:08:43 +0000 Subject: [PATCH] Revert "arm64: acpi: Enable ACPI CCEL support" This reverts commit d02c2e45b1e7767b177f6854026e4ad0d70b4a4d. Mauro reports that this breaks APEI notifications on his QEMU setup because the "reserved for firmware" region still needs to be writable by Linux in order to signal _back_ to the firmware after processing the reported error: | {1}[Hardware Error]: Hardware error from APEI Generic Hardware Error Source: 1 | ... | [Firmware Warn]: GHES: Unhandled processor error type 0x02: cache error | Unable to handle kernel write to read-only memory at virtual address ffff800080035018 | Mem abort info: | ESR = 0x000000009600004f | EC = 0x25: DABT (current EL), IL = 32 bits | SET = 0, FnV = 0 | EA = 0, S1PTW = 0 | FSC = 0x0f: level 3 permission fault | Data abort info: | ISV = 0, ISS = 0x0000004f, ISS2 = 0x00000000 | CM = 0, WnR = 1, TnD = 0, TagAccess = 0 | GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 | swapper pgtable: 4k pages, 52-bit VAs, pgdp=00000000505d7000 | pgd=10000000510bc003, p4d=1000000100229403, pud=100000010022a403, pmd=100000010022b403, pte=0060000139b90483 | Internal error: Oops: 000000009600004f [#1] SMP For now, revert the offending commit. We can presumably switch back to PAGE_KERNEL when bringing this back in the future. Link: https://lore.kernel.org/r/20251121224611.07efa95a@foz.lan Reported-by: Mauro Carvalho Chehab Signed-off-by: Will Deacon --- arch/arm64/kernel/acpi.c | 10 ---------- 1 file changed, 10 deletions(-) diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c index c022c1acb8c7..f1cb2447afc9 100644 --- a/arch/arm64/kernel/acpi.c +++ b/arch/arm64/kernel/acpi.c @@ -351,16 +351,6 @@ void __iomem *acpi_os_ioremap(acpi_physical_address phys, acpi_size size) * as long as we take care not to create a writable * mapping for executable code. */ - fallthrough; - - case EFI_ACPI_MEMORY_NVS: - /* - * ACPI NVS marks an area reserved for use by the - * firmware, even after exiting the boot service. - * This may be used by the firmware for sharing dynamic - * tables/data (e.g., ACPI CCEL) with the OS. Map it - * as read-only. - */ prot = PAGE_KERNEL_RO; break; -- 2.47.3